Technical Field
The present invention relates to the field of electronic displays, and more particularly to novel configurations for reducing mechanical strain in the manufacture and/or use of a flexible organic light-emitting display device.
Description of the Related Art
Flexible display, which can be bent without losing its functionality, is gaining significant attention as the next generation display technology because it provides several advantages over the conventional rigid displays. Features offered by the flexible displays include slimmer form factor, lighter weight, increased durability, and most of all, freedom to design unique electronic devices, which could not be achieved with conventional rigid displays. Generally, flexible substrates, such as very thin plastic or glass substrates, are used to provide mechanical flexibility necessary for the flexible displays. Once various components are formed on the flexible substrate, the flexible substrate can be placed on or even be wrapped around a base device and/or a support structure to manufacture a flexible display. As such, a range of revolutionary display devices, such as televisions with a curvature adjustable screen as well as portable electronics with a rollable display screen, can be manufactured by using the flexible display.
Despite significant technological advances, various challenges still remain in the field of flexible displays. In particular, manufacturing process for devices equipped with the flexible displays and the continuous flexing of such devices result in mechanical strain to various components in the flexible display. For example, the flexible display may need to be bent at or wrapped around an edge of a base structure, requiring a very small radius of curvature at the bent portion of the flexible display. Also, the flexible display may be tightly rolled or folded during the actual use of the device employing the flexible display. In such cases, several components of the flexible display are subjected to mechanical strain. Especially, wires and/or electrodes for such devices are usually sensitive to tensile, compression and/or shear stress, and thus the wires positioned at the bent portion of the flexible display are prone to crack/fracture when subjected to such mechanical stress.
Attempts have been made to reduce the crack and fracture of wires in the flexible displays. Most prior attempts were aimed at forming the wires with more ductile material or increasing the size of the wires to withstand the mechanical strain. Some methods involved adjusting the thickness of layers neighboring the wires or forming additional layers on or below the wires, so that the wires are within the neutral plane during the bending of the flexible display. However, the methods described above increases the thickness of the resulting display, and may even make it difficult to bend the flexible display to small radius of curvature. Therefore, such methods could not resolve the crack and fracture for the components positioned at a severely bent part such as the edge of the flexible display.
Accordingly, alleviating the mechanical stress on various components from the bending during manufacturing and/or using the flexible display is one of the major concerns in various devices employing the flexible display.